I remember when I was younger, about six to eight, I would have nightmares most nights, to the point where I would become afraid to go to sleep. I would remember nightmares vividly (don't most people?). I think the mechanism of fight-or-flight can help facilitate lucidity, it's a sudden shift in awareness, detaching the dreamer from much of the dream.
That general fear of dreams I had, I think led me to become lucid many nights as a child, though I think it could be hard to replicate that fear now I'm older.